An expanding measles outbreak in Wisconsin underscores the need for vaccination and awareness around symptoms and preventing the spread of the disease.
As of Sept. 18, 2026, Wisconsin Department of Health Services (DHS) had confirmed 167 cases of measles. It’s the highest number of cases in the state in decades.
“Getting the MMR vaccine is the most effective way to prevent contracting and spreading measles,” said Angela Divjak, MD, a family medicine physician with ThedaCare Physicians-Shawano. “With the number of cases continuing to increase, it’s also important to know what to do if you’re exposed to measles or develop symptoms. Because of how easily measles spreads, isolating from others is critical.”
Here, Dr. Divjak answers key questions around the Wisconsin measles outbreak.
What’s the Latest News?
Most of the Wisconsin cases in 2026 have been concentrated in the southwestern part of the state. Grant, Iowa and Lafayette counties have seen the highest number of cases. Vernon County recently confirmed two measles cases, and Marathon County announced one case related to out-of-state travel.
The MMR vaccination rate for Wisconsin kindergarteners was 85.1% for the 2025-26 school year. That’s nearly 10% shy of the national target of 95%. Wisconsin has the third-lowest MMR vaccination rate in the United States, according to the Centers for Disease Control and Prevention (CDC).
In the area ThedaCare serves, Marquette and Green Lake counties have the lowest rates of MMR vaccination for kindergartners, both at 68% according to Wisconsin DHS.
To date in 2026, the United States has confirmed more than 3,470 measles cases, up from 2,287 in 2025 and 283 in 2024.
What is Measles?
Measles is a highly contagious, serious disease caused by a virus. A person with measles can infect up to 90% of unvaccinated people with whom they come into close contact, according to the CDC. Measles can live for up to two hours in an airspace after an infected person leaves an area.
What are the Vaccine Recommendations?
“Getting vaccinated is easy and highly effective at preventing measles,” Dr. Divjak said. “Immunization protects you as well as those around you, including infants who are too young to get vaccinated.”
The CDC provides the following recommendations:
- Children need two MMR doses: one at 12-15 months and a second at 4-6 years. It’s safe for kids to receive MMR doses at the same time as they receive other vaccines.
- Older children, adolescents and adults need one or two doses of MMR vaccine if they don’t have evidence of immunity. Doses should be spaced at least 28 days apart.
- Anyone traveling internationally should be fully vaccinated before departing. Infants ages 6 months to 11 months should get one dose of the MMR vaccine before travel. Then they should get two more doses after their first birthday.
The MMR vaccine begins providing protection about two weeks after you receive it. Two doses of the vaccine are about 97% effective at preventing measles if you are exposed to the virus. One dose is about 93% effective, according to the CDC. Two doses of the MMR vaccine provide strong, lifelong protection against measles for most people.
If you are unsure of vaccination status for yourself or a loved one, you can log into MyThedaCare and select Immunizations to view your immunization record. You can also obtain this information from the Wisconsin Immunization Registry.
What Are the Symptoms of Measles?
Measles is transmitted through direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs or sneezes.
Symptoms typically appear seven to 14 days after exposure. People often experience symptoms in waves, according to the CDC.
7-14 days after measles infection — initial symptoms:
- High fever (may spike to more than 104°F)
- Cough
- Runny nose
- Red, watery eyes (conjunctivitis or pink eye)
2-3 days after symptoms begin — tiny white spots:
- Tiny white spots (Koplik spots) may appear inside the mouth two to three days after symptoms begin.
3-5 days after symptoms begin — measles rash:
Measles rash appears three to five days after the first symptoms. It usually begins as flat red spots that appear on the face at the hairline. They then spread downward to the neck, trunk, arms, legs and feet.
- Small raised bumps also may appear on top of the flat red spots.
- The spots may join together as they spread from the head to the rest of the body.
- When the rash appears, a person’s fever may spike to more than 104°F.
Measles can cause severe health complications. These include pneumonia, encephalitis (brain inflammation) and death. Nationally, about one in five unvaccinated people who get measles are hospitalized.
What Should I Do if I Have a Measles Exposure or Symptoms?
“Because measles is highly contagious, it’s important to call the clinic or hospital before coming in for evaluation,” Dr. Divjak said. “ThedaCare also offers virtual care.”
People with measles should isolate and stay home for four days following the onset of the rash, according to the American Academy of Pediatrics. The onset of the rash is considered day zero.
How Can I Protect Myself and My Family?
“I can’t stress enough that vaccination is the most important step you can take,” Dr. Divjak said. “Prevention is key. Beyond home comfort measures, supportive care and steps to prevent complications, there’s no specific treatment available for measles once it occurs.”
Schedule an MMR vaccination today
Call the Vaccine Clinic Line at 920-702-6380 or schedule online. Vaccinations also are available at selected retail pharmacy locations for those ages 6 and older.
